Valence Band Engineering of Layered Bismuth Oxyhalides toward Stable Visible-Light Water Splitting: Madelung Site Potential Analysis
Valence Band Engineering of Layered Bismuth Oxyhalides toward Stable Visible-Light Water Splitting: Madelung Site Potential Analysis
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DOI：
10.1021/jacs.7b11497
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发表时间：
2017-12-27
影响因子：
15
通讯作者：
Kageyama, Hiroshi
中科院分区：
文献类型：
--
作者：
Kato, Daichi;Hongo, Kenta;Kageyama, Hiroshi
层状氯氧化物Bi_4NbO_8Cl是一种可见光响应的水裂解催化剂，其显著的稳定性归因于价带中O-2 p轨道的高度分散，但其起源尚不清楚。本文系统地研究了BiOX（X = Cl，Br，I），Bi_4NbO_8X（X = Cl，Br），Bi_2GdO_4X（X = Cl，Br）和SrBiO_2X（X = Cl，Br，I）四个系列的层状卤氧化铋，发现阴离子的马德隆位势捕获了这些材料的价带结构的本质特征。萤石状嵌段中的氧阴离子（例如，[Bi_2O_2]板条）负责价带的上移，并且静电不稳定的程度取决于构建层及其堆叠顺序。这项研究表明，马德隆分析，使预测和设计的价带结构的铋和其他层状卤氧化物，甚至是适用于化合物的DFT计算是难以执行。
A layered oxychloride Bi4NbO8Cl is a visible-light responsive catalyst for water splitting, with its remarkable stability ascribed to the highly dispersive O-2p orbitals in the valence band, the origin of which, however, remains unclear. Here, we systematically investigate four series of layered bismuth oxyhalides, BiOX (X = Cl, Br, I), Bi4NbO8X (X = Cl, Br), Bi2GdO4X (X = Cl, Br), and SrBiO2X (X = Cl, Br, I), and found that Madelung site potentials of anions capture essential features of the valence band structures of these materials. The oxide anion in fluorite-like blocks (e.g., [Bi2O2] slab in Bi4NbO8Cl) is responsible for the upward shift of the valence band, and the degree of electrostatic destabilization changes depending on building layers and their stacking sequence. This study suggests that the Madelung analysis enables a prediction and design of the valence band structures of bismuth and other layered oxyhalides and is applicable even to a compound where DFT calculation is difficult to perform.